Preoperative speech deficits in children with posterior fossa tumours (PFTs) may be linked to postoperative speech impairment (POSI), a hallmark of posterior fossa syndrome, yet this relationship remains underexplored. POSI is characterized by mutism or markedly reduced speech that resolves within weeks to months but often leaves persistent motor-speech deficits. Most existing literature has focused on postoperative outcomes, with limited attention to preoperative speech function. We therefore systematically investigated this association by analyzing perceptible motor-speech features in a large cohort of patients scheduled for surgery within the European Study of Cerebellar Mutism Syndrome. We included data from 135 children which formed three age-and sex- comparable groups: 16 patients who later developed POSI, 11 were mute and five had severely reduced speech (3;9–14;4 years), 62 patients with habitual speech (3;2–17;11 years), and 57 healthy controls (3;0–18;1 years). Patients were Italian-, Dutch-, and English-speaking, while controls were Dutch- and Italian-speaking. Four speech-language therapists rated participants’ narrative recordings on 23 speech features (e.g., distorted vowels, imprecise consonants, stuttering, and hoarseness). Group comparisons revealed significant preoperative differences between the children who later developed POSI and the children with habitual speech in both hypernasality and in phonation-respiration (e.g., leaky, hoarse, and strained voice). In addition, patients who later developed POSI showed impairment compared to healthy controls in prosody (e.g., speech rate, excess and equal stress) and articulation (e.g., distorted vowels, imprecise consonants, sequencing errors). Patients with habitual speech differed from the controls in hypernasality and prosody. Moreover, age influenced the severity of articulatory and prosodic symptoms, with younger patients showing greater impairment. Children with PFT show signs of speech impairment preoperatively relative to healthy controls. When comparing patients, those later developing POSI show more severe impairments related to resonance and voice quality. This suggests possible differences in the degree to which speech-related underlying anatomical substrates were compromised, and these early differences may represent potential predictors of later POSI. These findings highlight the value of preoperative assessment for identifying children at a heightened risk of POSI, opening opportunities for prehabilitation - targeted early intervention in the form of speech therapy - to strengthen the speech-motor networks.

BACKGROUND:Word finding - the ability to retrieve and produce appropriate words in response to prompts or visual stimuli - is impaired in some patients with a posterior fossa tumour. Yet, few studies use preoperative assessment as a baseline, and an in-depth linguistic analysis of tasks assessing word-finding ability remains limited. The current study aims to fill this knowledge gap by analysing pre- and postoperative word-finding ability and identifying its linguistic predictors. METHOD:38 English-speaking patients (19 males and 19 females), aged between 2,5 and 17,6 years and diagnosed with posterior fossa tumours were assessed before and after surgery. Performance was assessed using a picture-naming task, Wordrace, measuring both accuracy and reaction times. These measures were interpreted in terms of their correlation with linguistic levels (i.e., lexical, semantic, phonological). RESULTS:Patients exhibited a significant slowing in word-finding speed following surgery, while accuracy remained stable across assessment points. Despite this decline in speed, we did not find evidence for a change in the influence of psycholinguistic factors on word-finding ability in our sample. Lexical-semantic variables predicted word-finding speed, whereas accuracy was influenced only by lexical variables. CONCLUSION:The findings suggest that although general performance declined postoperatively, we did not find evidence in our sample of disruption to the underlying linguistic processes engaged during word-finding. However, the absence of control group limits interpretation, and future studies comparing patients with healthy controls may reveal more subtle differences. The study emphasises the importance of longitudinal assessment in patients with posterior fossa tumours and future studies should incorporate additional timepoints to examine the potential effects of radiotherapy and chemotherapy on word-finding over time.

Purpose Preoperative speech deficits may be linked to postoperative speech impairment (POSI), a hallmark of posterior fossa syndrome, yet this relationship remains underexplored. POSI is characterized by mutism or markedly reduced speech that resolves within weeks to months but often leaves persistent motor-speech deficits. Most existing literature has focused on postoperative outcomes, with limited attention to preoperative speech function. We therefore systematically investigated this association by analyzing perceptible motor-speech features in a large cohort of patients scheduled for surgery within the European Study of Cerebellar Mutism Syndrome. Method We included data from 135 children which formed three age-and sex- comparable groups: 16 patients who later developed POSI, 11 were mute and five had severely reduced speech (3;9–14;4 years), 62 patients with habitual speech (3;2–17;11 years), and 57 healthy controls (3;0–18;1 years). Patients were Italian-, Dutch-, and English-speaking, while controls were Dutch- and Italian-speaking. Four speech-language therapists rated participants’ narrative recordings on 23 speech features (e.g., distorted vowels, imprecise consonants, stuttering, and hoarseness). Results Group comparisons revealed significant preoperative differences between the children who later developed POSI and the children with habitual speech in both hypernasality and in phonation-respiration (e.g., leaky, hoarse, and strained voice). In addition, patients who later developed POSI showed impairment compared to healthy controls in prosody (e.g., speech rate, excess and equal stress) and articulation (e.g., distorted vowels, imprecise consonants, sequencing errors). Patients with habitual speech differed from the controls in hypernasality and prosody. Moreover, age influenced the severity of articulatory and prosodic symptoms, with younger patients showing greater impairment. Conclusion Children with PFT show signs of speech impairment preoperatively relative to healthy controls. When comparing patients, those later developing POSI show more severe impairments related to resonance and voice quality. This suggests possible differences in the degree to which speech-related underlying anatomical substrates were compromised, and these early differences may represent potential predictors of later POSI. These findings highlight the value of preoperative assessment for identifying children at a heightened risk of POSI, opening opportunities for prehabilitation - targeted early intervention in the form of speech therapy - to strengthen the speech-motor networks.

Cerebellar mutism syndrome (CMS) has received increasing attention over the last decades as a complication of posterior fossa tumour surgery in children. Risk factors, aetiological aspects, and treatment measures of the syndrome have been investigated, yet the incidence of CMS remains unchanged. Overall, we are currently able to identify patients at risk, but we are unable to prevent it from occurring.Once CMS sets in, several symptomatic pharmacological treatments have been suggested, but only in smaller case series and not in randomized controlled trials, and it is not clear whether the treatment or time itself had a helpful effect.Within weeks to months, most patients regain their ability to speak after a phase with mutism or severely reduced speech; however, many patients continue to have speech and language deficits. At this point, anti-cancer treatment with chemotherapy and radiotherapy may be of focus more than the prognosis of CMS; however, many patients continue to have speech and language problems for months and years to come, and they are at high risk of other neurocognitive sequelae as well.Without reliable measures to prevent or treat the syndrome, we may look towards improving the prognosis of speech and neurocognitive functioning in these patients. As speech and language impairment is the cardinal symptom and late effect of CMS, the effect of intense and early-onset speech and language therapy as a standard of care in these patients should be investigated in relation to its effect on regaining speech capacity.

Central nervous system tumours constitute 25% of all childhood cancers; more than half are located in the posterior fossa and surgery is usually part of therapy. One of the most disabling late effects of posterior fossa tumour surgery is the cerebellar mutism syndrome (CMS) which has been reported in up to 39% of the patients but the exact incidence is uncertain since milder cases may be unrecognized. Recovery is usually incomplete. Reported risk factors are tumour type, midline location and brainstem involvement, but the exact aetiology, surgical and other risk factors, the clinical course and strategies for prevention and treatment are yet to be determined.

CMS-06. THE NOPHO-EUROPEAN STUDY ON CEREBELLAR MUTISM SYNDROME (CMS) Morten Wibroe1, Shivaram Avula2, Johan Cappelen3, Charlotte Castor4, Niels Clausen5, Irene Devenney6, Greg Fellows21, Pernilla Grillner7, Ramneek Gupta8, Bengt Gustavsson7, Mats Heyman7, Stefan Holm7, Atte Karppinen9, Rosita Kiudeliene10, Camilla Klausen1, Päivi Lähteenmäki11, Tuula Lönnqvist9, Stephen Lowis21, Conor Mallucci2, René Mathiasen1, Mattias Mattson12, Pelle Nilsson13, Kristiina Nordfors14, Per Nyman6, Karsten Nysom1, Karin Persson15, Jouni Pesola20, Barry Pizer2, Olof Rask4, MagnusSabel16,KjeldSchmiegelow1,AstridSehested1, IngridTonning-Olsson4, Ingrid Kristin Torsvik17, Kirsten van Baarsen18, David Walker19, Mia Westerholm-Ormio9, Barbara Zetterqvist7, and Marianne Juhler1; University Hospital Rigshospitalet, Copenhagen, Denmark; Alder Hey Children’s Hospital, Liverpool, UK; St Olavs University Hospital, Trondheim, Norway; Skåne University Hospital, Lund, Sweden; University Hospital Aarhus, Skejby, Denmark; Linköping University Hospital, Linköping, Sweden; Karolinska University Hospital, Stockholm, Sweden; Technical University of Denmark, Copenhagen, Denmark; Helsinki University Hospital, Helsinki, Finland; HospitalofLithuanian Universityof Health Sciences Kauno Klinikos, Kaunas, Lithuania; Turku University Hospital, Turku, Finland; University Hospital of Umeå, Umeå, Sweden; Uppsala University Hospital, Uppsala, Sweden; Tampere University Hospital, Tampere, Finland; BarnReHab Skåne, Lund, Sweden; Sahlgrenska University Hospital, Göteborg, Sweden; Haukeland University Hospital, Bergen, Norway; Radboud University Medical Centre, Nijmegen, The Netherlands; Children Brain Tumour Research Centre, Nottingham, UK; Kuopio University Hospital, Kuopio, Finland; Bristol Royal Children’s Hospital, Bristol, UK BACKGROUND: The cerebellar mutism syndrome (CMS) is one of the most disabling late effects afterneurosurgery foraposterior fossa tumour inchildhood. The reported incidences vary substantially in previous studies. AIMS: Pathophysiology is unknown, but damage to cerebello-thalamo-cerebral circuits is likely.Thestudyfocusesontheriskfactors fordevelopmentandseverityofCMS including surgery (approaches, techniques and tissue and vascular damage, reoperation) and host genome variants. METHODS: Multicentre study developed as a NOPHO collaborative study coordinated from Righospitalet, Copenhagen with online data registration and database management at Karolinska, Stockholm and quarterly online participant meetings. Registration includes clinical data and speech samples collected preoperatively and at four defined postoperative points for the subsequent 12 months. Therapy, including neurosurgery, is by local standards. A blood sample for genetic analysis is collected from all patients. Imaging is collected and reviewed centrally. RESULTS: The study aims to recruit 550 children. It opened in five Nordic and Baltic countries during 2014/2015; in the Netherlands in February 2016 and will open in the UK during2016.Two Germancentreswill join in2017.The target accrualof550 patients will be reached by the end of 2018. As of February 2016, 67 patients have been included from 12 centres. Mutism has occurred in 7 cases. CONCLUSION: The study will be the largest prospective international study on CMS to date, and the first one to 1) systematically register surgery, use of steroids, standardized speech samples and 2) to investigate the influence of host genome. Neuro-Oncology 18:iii16–iii17, 2016. doi:10.1093/neuonc/now066.5 #The Author(s) 2016. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com. at D T U L irary on Jauary 3, 2017 http://neuro-oy.oxfordjournals.org/ D ow nladed from